Motor Control Method for Stable Minimal Velocity Operation
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Solution Overview
Problem
Conventional motor control methods, such as closed-loop feedback control, struggle to maintain stability and accuracy when driving a motor at minimal velocity, especially when the load on the motor fluctuates, leading to issues like incomplete capping operations in inkjet printers and vibration/noise during capping.
Innovation Solution
A motor control method that adjusts the driving force of a motor by increasing it from an initial value by a specified amount in a specified period every time the driving target is driven for a specified amount, based on the current driving status, including driving force, time, and velocity, to maintain target velocity despite load fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If feedback control is applied to drive a motor at minimal velocity, then the motor can operate at low speed, but the driving target stops completely due to excessive deceleration control
Solution Approach 1:
The control method dynamically adjusts the driving force by incrementally increasing it by a predetermined amount in each control period when the driving target is moving at minimal velocity. This dynamic adjustment prevents the driving force from becoming too small and causing complete stoppage, thereby maintaining controllability while operating at minimal velocity.
Solution Approach 2:
The invention changes the control parameter (driving force) by adding a predetermined increment amount in each control period when minimal velocity is detected. This parameter change ensures the driving force remains sufficient to prevent complete stoppage and maintain system controllability.
2Speed
If feedback control is applied to drive a motor at minimal velocity, then the motor can operate at low speed, but vibration and noise occur due to load fluctuations
Solution Approach 1:
The control method dynamically increases the driving force by a predetermined amount in each control period when minimal velocity is detected. This dynamic adjustment compensates for load fluctuations that cause vibration and noise, ensuring smooth operation at minimal velocity.
Solution Approach 2:
The invention maintains continuous useful action by ensuring the driving force never becomes too small through incremental increases. This continuous sufficient driving force prevents interruptions and vibrations caused by load variations, eliminating harmful effects.
3Speed
If feedback control is applied to drive a motor at minimal velocity, then the motor can operate at low speed, but the capping operation becomes incomplete due to insufficient driving force
Solution Approach 1:
The control method dynamically adjusts the driving force by incrementally increasing it when minimal velocity is detected during capping operations. This ensures sufficient driving force is maintained to complete the capping operation fully, preventing incomplete capping while operating at minimal velocity.
Solution Approach 2:
The invention changes the driving force parameter by adding a predetermined increment in each control period during minimal velocity operation. This parameter change ensures the driving force remains sufficient to complete capping operations accurately, improving manufacturing precision.
4Speed
If feedback control is applied to drive a motor at minimal velocity, then the motor can operate at low speed, but the control complexity increases due to load fluctuation compensation
Solution Approach 1:
The control method implements a simple dynamic adjustment mechanism that automatically increases driving force by a predetermined amount when minimal velocity is detected. This straightforward dynamic control handles load fluctuations without requiring complex control algorithms or additional sensors.
Solution Approach 2:
The invention enables the control system to self-adjust the driving force automatically based on velocity detection. The system serves itself by detecting minimal velocity and autonomously increasing driving force, eliminating the need for complex external control mechanisms.
Data Source
AI summary
When motor drive is initiated, firstly a PWM value at time of driving initiation is set to an initial setting value start_pwm1, and gradually increased by a specified amount in specified period. When an encoder edge is detected, the PWM value is reset to the initial setting value, and increased again in the same manner. From second edge detection, next PWM initial value is set corresponding to a PWM value at the time of edge detection. If the PWM value at the time of edge detection is larger than det_pwm_max owing to load on the motor becoming large and thereby driving velocity becoming slower, a PWM value which is larger than previous PWM initial value is set as a new PWM initial value. The driving target can be driven stably irrelevant to fluctuation of the load on the motor.